Nucleic acids 2 Flashcards
Chromatin DNA organization mitochondrial cellular DNA gene alteration and arrangement
It is formed by further organization of chromatin and chromatid and has two-fold symmetry at metaphase
Chromosomes
⮞ It is an adenine-thymine (A-T) rich region
⮞ site where identical sister chromatids are connected
Centromeres
⮞ centromere-protein complex
⮞ provides an anchor for mitotic spindle
Kinetochore
⮞ contains altered nucleosome structures
⮞ DNA in these regions are susceptible to “DNase I” digestion
ACTIVE REGIONS
Type of point mutation with NO changes in amino acid and is at 3RD base of codon
Silent type
What is the chromatin composed of?
⮞ DNA
⮞ RNA
⮞ histones
⮞ non-histone proteins
⮞ It is a complex of certain histones
⮞ DNA that looks like rosary beads
Nucleosome
H1 phosphorylation: chromosome condensation
general core histone acetylation: ___________
chromosome assembly
What is the associated process for ADP-ribosylation of histones?
DNA repair
What is the associated process of Histone Methylation?
activation and repression of gene transcription
H3 and H4 Acetylation 🡆
Inactivation/activation of gene transcription
What is composed of two of each of CORE HISTONES?
histones octamer
Significant function of Histone Chaperones?
It facilitates chromatin assembly factors
A constitutive heterochromatin is essentially INACTIVE because
it is always condensed (if chromatin is condensed, access by transcription enzyme is limited)
Site of enhancers for binding transcriptional activator proteins in DNA
Active regions
Region rich in 5-methyldeoxycytidine
Inactive regions
What do you get when you unpack chromosomes?
dsDNA (double-stranded DNA)
Type of RNA: cellular machinery for protein synthesis
Ribosomal RNA (rRNA)
Type of RNA: adapter for translation of RNA into specific sequences of amino acids in peptides/proteins
Transfer RNA (tRNA)
Denaturation of DNA: leads to an increase in absorbance of purine and pyrimidine bases
Hyperchromic shift (remember: absorbance = concentration)
In terms of denaturation of DNA, increasing the temperature means you increase
ENTROPY (thus disruption of H-bonds)
What trinucleotide sequence leading to Fragile X syndrome?
CGG
this trinucleotide CGU means
Arginine
this trinucleotide CTG leads to
myotonic dystrophy
this trinucleotide CAG leads to
huntington’s disease
spinobulbar muscular atrophy
kennedy disease
What describes a PSEUDOGENE?
processed genes containing non-sense codons
